The suicidal kamikazes were the Japanese empire’s last ditch effort to slow advancing Allied forces. Viewed as tragic heroes today, most of them sortied out from Kyushu and many of the former kamikaze bases have sprouted memorial hall museums and have had their surviving ruins preserved. Almost all are in honor of the airborne kamikazes, but in Oita Prefecture’s Hiji Town they remember the seaborne Kaiten manned torpedoes that once trained in Beppu Bay.
The Kaiten program used an enlarged Type 93 torpedo with a larger warhead that the standard Type 93 and a cockpit section for its living guidance system. The program began with plans for a pilot-guided torpedo in 1943; in the earliest forms there was an escape mechanism for the pilot to eject before hitting the target. This changed to a pure suicide weapon in August 1944.
The first Kaiten sortie on Nov. 20, 1944 scored a success with the sinking of fleet oiler USS Mississinewa (AO-59) at Ulithi atoll. The total number of Kaiten kills is unknown but only two have been confirmed. A total of 106 Kaiten were launched at targets and 145 pilots died in combat and training. Eight submarines were lost while performing Kaiten operations.
To train the pilot cadre, bases were discreetly constructed or converted from pre-existing facilities around Japan’s Seto Inland Sea where they could practice in relative safety and secrecy. Oga village (now part of Hiji) was chosen as the site of an Imperial Japanese Navy weapons plant in 1941-42, but the plan was scrapped in 1943 due to more pressing wartime concerns. After the Kaiten program began the plan to build at Oga was revived in autumn 1944. Using civil engineers, Korean conscripts and high school students for labor, the fourth and final Kaiten training base opened on Apr. 25, 1945 with Capt. Yamada Morishige in command and 2,000 personnel attached. A month later training began in Beppu Bay.
Their first operational sortie was on Aug. 3 when eight Kaiten were sent out and a second was being prepared when the war ended. After the cessation of hostilities all Kaiten were scuttled in the bay before the base was turned over to American forces on Aug. 31, 1945.
About half an hour away from (literal) hot spot Beppu, Japan’s premiere onsen town, Hiji’s primary attractions are the Hello Kitty theme park Sanrio Harmonyland and castle ruins. There may be lines to see what Kitty-san has to offer (not really, this is a pretty off the beaten track location) but when we arrived at Kaiten Memorial Park there was barely anyone around to disrupt the tranquility.
The park is new enough rust hasn’t formed on the perfect full-scale Kaiten replica beside the ruins of the torpedo adjustment pool, at the Kaiten Memorial Park. Two statues, one of a Kaiten pilot and another of the mother and sister left behind stand beside it.
Those he leaves behind.
Like a small outdoor museum, a long wall explains the story of the Kaiten and their role in World War II. A gazebo carries maps for visitors to take with them to discover and explore Hiji’s Kaiten training base ruins and tunnels which still riddle the surrounding hills.
It was the latter that surprised me as I’ve seen the memorial park and hilltop shrine online but nothing had ever mentioned the tunnels and other small ruins. It was beginning to look like I had another Usa on my hands.
My time was limited so I struck out for the easy to find tunnels on a nearby farm road and the hilltop Kaiten Shrine.
A pair of tunnels are at the foot of the hill, one cuts through entirely and light can be seen from the other end. Its near the water and Kaiten were stored here, rails used to run from the tunnel so that they could easily be led to the launch area. It’s similar to the setup at Ozushima Kaiten training base and the pier rails at Kawatana’s Katashima Torpedo Testing Facility though the rails here are long gone.
The small shrine has a much scaled down Kaiten model and the remains of a Kaiten propeller and engine on outdoor display. They’re covered but ideally should be better housed to keep the elements from eating away at them.
The two tunnels near the shrine have little boundary markers to keep people from walking in, at least as a recommendation to stay out, and nice placards but the tunnels down the nearby canal-side road do not. I recommend leaving your car parked at the Kaiten Memorial Park when going to visit those tunnels. The road is not paved, a bit muddy and uneven and the distance not far enough to justify driving and risking vehicle damage.
A bit wilder the further I got, the grass taller and trees thicker, each tunnel entrance felt like discovering some lost place. I was worried about boars but saw no warning signs for them.
These tunnels made me regret not coming with a flashlight and some friends. There’s a complete set of storage tunnels, laterals and horizontals, and not a single “keep out” warning in sight. Past that collection was a much larger U-shaped tunnel I did walk through. It was muddy and bare but something to see.
It’s rare to find old navy tunnels in the wild, on a marked map and yet not barred and gated to prevent entry and going by the map these ones look extensive. Not quite an underground headquarters complex, but still more than your average evacuation factory tunnels or storage tunnels.
To find these tunnels, when walking from the Kaiten Memorial Park to the hilltop shrine you have to cross a road, before crossing look to the right. To the side of the main road is a smaller road along the canal. Follow it and you’ll find the tunnels.
Some other ruins that are listed are in awkward places, such as a farmer’s backyard and others almost completely inaccessible without a machete to cut through forest as far as I can tell, though given that they are on the map I assume that they want people to see them.
There’s a few other smaller bit of ruins immediately around and inside the memorial park, just some traces of wall or fixture mounts on the ground and building remains behind the coffee shop. While I looked at that, my wife picked up some local fried fish from a diner down the road and we ate in the gazebo. It had been rainy and grey when we arrived but the weather had broken now and the sunlight playing off the golden grass, Kaiten and statues made for a good last look before continuing on our journey.
We visited while on our way back home after a few days in Beppu, but this park can be easily linked to a trip to Usa, which is less than an hour away and has hours of old base ruins to explore, hardened aircraft shelters, a replica Ohka suicide bomb, Zero fighter and half-cockpit you can climb into. Hiji has material on all the Kamikaze museums and memorial halls on Kyushu, which is a nice touch for letting people who are interested in these places know that there really is so much more to see if you know where to look.
ADDRESS
5673 Oga, Hiji, Hayami-gun, Oita 879-1504